1. Field of the invention
The present invention is generally concerned with delivering vertically disposed objects one by one to a conveyor, for example bottles or other hollow articles made from synthetic material, and in particular with servicing an installation for applying any form of treatment to such objects.
2. Description of the prior art
The invention is more particularly directed to distribution devices of the kind comprising a hopper adapted to receive the objects in bulk and having an inclined axis, an inclined disk constituting the bottom of the hopper and adapted to rotate about the inclined axis, a plurality of openings at the periphery of the disk each adapted to receive one object, an inclined plate beneath and parallel to the disk, a release opening in an upper part of the plate aligned with the path of movement of the openings as the disk rotates, and a plurality of chute members between the hopper and the conveyor adapted to move under the release opening and each adapted to receive the objects one by one.
Thus each time that one of the objects to be distributed, entrained by the rotating disk at the bottom of the hopper and properly oriented horizontally by the opening in the rotating disk in which it must have become at least partially inserted in order to be entrained by it, arrives at the release opening from the hopper it falls under its own weight, simultaneously tilting about a horizontal axis, into the chute member beneath the release opening and thus reaches the conveyor, in the required vertical disposition.
A distribution device of this kind is described, for example, in French Pat. No 2 370 656.
In this disclosure, however, the chute members are constrained to rotate with the rotating disk of the hopper and, like the disk, they therefore constitute part of the hopper, being disposed in a compartment under the bottom of the hopper.
Although this arrangement can be satisfactory in some applications, and in particular those for which a relatively moderate distribution rate may suffice, it does have various disadvantages.
Firstly, because of the compartment that it has to comprise to accommodate the chute members the hopper is of relatively complex, frustoconical shape at the bottom.
Also, the inertia of the rotating mass is increased by that of the chute members, so that the driving means have to be rated to cater for this additional inertia.
Furthermore, because they are constrained to rotate with the rotating disk, the axis of which is inclined to the vertical, like that of the hopper, as the chute members move under the release opening from the hopper, one by one, they remain vertical for only a relatively short time interval, insufficient in any event for the objects to be distributed which fall into them to have time to pass through them and be released from them.
In practise, they can only be released on the next rotation and arrangements have to be made so that two objects to be distributed can be housed simultaneously in a chute member, stacked one on the other but appropriately isolated from each other.
Apart from the fact that the inertia of the rotating assembly is even further increased by the second series of objects to be distributed which has in this way to be driven through one complete revolution, and although the inevitable result is some increase in mechanical complexity because of the height that is then required for the chute members and the necessity to divide them vertically into two sections to secure the necessary separation of the two objects to be distributed which can be present in them simultaneously, the risk of the objects jamming in the chute members is commensurately increased.
Being accommodated within a compartment of the hopper, the chute members are difficult to gain access to, whereby any jamming of an object to be distributed in a chute member inevitably entails considerable disruption of the functioning of the installation, compromising its efficiency.
Finally, and most importantly, as the chute members are driven in rotation and are operative at the periphery of the hopper, and thus on a circumference of considerable diameter, when the objects to be distributed are released they are subjected to a high centrifugal force which seriously compromises their stability when they are taken up by the conveyor, with the attendent risk that they may topple over even if the conveyor is provided with suction means in an attempt to overcome this problem.
Once again, any unwanted wobbling of objects on the conveyor as they reach it can only be seriously prejudicial to functioning of the installation.
To keep the effects of centrifugal force within acceptable limits it is in practise necessary to accept a relatively moderate diameter for the hopper and/or a relatively moderate speed of rotation for the disk which forms its bottom, entailing a limitation on the capacity of the installation and in particular on the rate of distribution that it is able to achieve.
A general objective of the present invention is to provide an arrangement which, whilst making it possible to circumvent these disadvantages, offered the advantage of making it possible to achieve high rates of distribution, as well as other advantages.